Electric boiler



Jan. 6, 1925.

BEST AVAILABLE COPY l v I 1,522,214 H. L. UNLANDI zmc'm'c BQILER FiledNov. 22, 1925 Inventor:

Harry Luhlanol,

' HssAt-comy,

Patented Jan. 6, 1925.

BEST AVAILABLE COP.

, UNITED STATES PATENT OFFICE.

KARRY I1. UiNLAND, OF SCHENECTADY,"NEW YOBK, ASSIGNOB T GENERAL ELECTRICCOMPANY, A CORBQRATION OF NEW YORK.

. nmzc'rmc momma Application filed November 22, 1923. Serial No.676,423.

limited thereto.

For certain applications, the condition is met with where a small amountof steam is required-continuously and where for brief intervals acomparatively large amount. is required. For example. in connection withsteam turbines itmay be desirable to keep a turbo-gcnerntor setoperatinp continuously at practically no load in order to have it warmedup and running ready to assume a load in case of some emergency. In sucha (use it is ueccssarv, of course, to have available a supply of steamfor, operating the turbine which supply is of suflicient volume to carrythe emergency load, andthe object of my invention is to provide anelectric boiler particularly adapted for use under these operatingconditions.

1 For a consideration of what I believe to be novel in my invention.attention directed tothe accompanying description and the claimsappended thereto.

In the drawing the figure is a, diagrammatic view of an-elcctric boilerembodying my invention. Y

Accordin to my invention, I provide an electric boiIer comprising a drum1 which contains a supply of water 2, and a shell 3 directly adjacentthe drum and containing the electric heating elements 4. In the presentinstance the electric heating elements 4 are in the form of electrodescar- 'ried by supporting conductors 5 which project through insulators 6to the outside of the shell. Three electrodes are shown which adaptthe'boiler for connection'to a source. of three-phase alternatingcurrent. The lower end of electrode shell 3 is connected to drum 1 by anumber of openings 7 and also by a conduit 8 controlled by a valve 9having an operating handle 10 lo cated outside of drum' 1 so that valve9 may l be adjusted at any ,WhlCll may be driven in any suitablemantime. At 11 is a pump ner and which draws water from drum 1 through aconduit 12-and delivers it to shell 3 through a conduit 13. Conduit 13has two-branches 14: and 15 each provided with a regulating valve 16.Byadjusting valves 16 and also valve 9 the rapidity of the circulationof the water from drum 1 to shell 3 may be regulated. The upper portionof drum 1 and shell 3 wluch are steamspaces are connected by conduits 17and 18 to a.

conduit. 19 which conveys steam to the point of consumption. i

Arranged i conduit 19 is a pressure re ducing valve lo-which is set toeffect a substantial reduction of pressure in the steam flowing throughit so that itmaintams on its inlet side, that is in drum 1 and shell 3 apressure substantially higher than is appliedto the point ofconsumption. for example, the steam turbine inlet. This means,therefore; that there is a substantial difference in pressure betweenthe steam generated and that'applied'to the turbine inlet or-otherconsumtlon point. Valve 20 may be of any suita 1e structure. In the presentinstance, a known type is indicated, the amount which the valve isopened befng-- under the influence of the pressure on time discharge.side of the valve so as to maintain such pressure substantiallyconstant, as is well understood. With such a .valve. when the pressureonthe low pressure side decreases due to an increase in the demand forsteam the valve is automatically opened further while when such pressureincreases, the valve will be moved toward closed position. Inconduit 19I provide also preferably, a non-return valve 21 which may be of anysuitable structure and serves to-prevent flow from conduit 19 biicktoward the boiler.v 22 indicates a conduit through which makekup watermay be supplied to the boiler. Y p

In operatiompum 11 continuously circulates water from rum 1 throughpipes 12 and l3to shell from whence rur back to drum 1 throughopenings-"7 an.

conduit 8', and the pump and valve 9 are so BEST AVAlLABLE COP\ depthto. which the electrodes are submerged, as is well understood, and theregnlation is made such that the electrodes will be submerged to such adepth as to genei'atesuilieicnt steam to supply the normal minimumrequirements at the point of consumption .for example, iii.the case of asteam tur iine to keep the turbine operating idle, and in additioncharge and keep charged uith heat the water in drum l. Drum 1 is incommunication with the steam space in electrode shell 3 through pipes 17and 18 so that the pressure in drum 1 is the same as that of the steambeing generated,

' and the circulation of the water from drum 1 to the electrode shell 3maintained suiliciently rapid so that the water in drum 1 will hemaintained at substantially the same temperature as that-in shell 3, i.e., at the temperature corresponding to the temperature of saturatedsteam at the pressure' in the boiler.

As stated above, the electric boiler-generates sufiicient steam tosupply the "normal requirements tothe point of consumption. In case of asudden large demand, the pressure on the discharge side of the reducingvalve 20 will decrease which results in a further opening of valve 20and a more rapid flow of steam through it and hence a reduc- 1 tion ofthe pressure in drum 1 and shell 3.

heat storage drum 1 may he made such as to meet the operating conditionsmet-with in any particular instance. The arrangement finds especial utilityhowever, where the normal requirements are comparatively small ascom ared to the occasional or emergency demand, and the emergency demandOccurs but seldom, for under these circum-- stances the electric boilerneed be only large enough to meet the normal demand-for steam and torecharge the heat storage drum 1 within a specified time.

' In accordance with the provisions of the patent statutes, I havedescribed the principle of operation of my invention, together with theapparatus which I now consider to represent the best embodiment thereof,but I desire to have it understood that the apparatus shown is onlyillustrative and that the invention may be carried out by other means.

, \Vhat I claim as new anddesire to secure by Letters Patent of theUnited States, is,-

1. In combination, an electric boiler comprising a shell, electricheating elements in the shell and a heat storage drum in directcommunication with the shell, means for circulating liquid from the drumto the shell,

a discharge conduit which leads to apoint of consumption, and saidconduit. g, 2. In combinatlon, an electric boiler com- ,prising a shellof smaller capacity and a heat storage drum of larger capacity,electrodes in said shell, means for circulating liquidfrom the drum tothe shell and back to the drum, means fol-regulating the circulation, adischarge. conduit in communication with both the shell and lucing valvein said conduit.

' In witness whereof, I have hereunto set my hand this 21st day ofNovember, 1923.

, HARRY L; UNLAND.

a reducing valve indrum, and a re-

